Endless track for traction of a vehicle

ABSTRACT

A track for traction of an off-road vehicle such as an agricultural vehicle, a construction vehicle, a snowmobile, or another vehicle operable off-road. The track is mountable around a track-engaging assembly comprising a drive wheel for driving the track. The track is elastomeric to be flexible around the track-engaging assembly. The track comprises an inner surface for facing the track-engaging assembly, a ground-engaging outer surface for engaging the ground, and a plurality of traction projections projecting from the ground-engaging outer surface. The track may have various features to enhance its traction, its floatation, and/or other aspects relating to use and performance of a track system of the vehicle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional PatentApplication No. 61/794,088 filed on Mar. 15, 2013 and herebyincorporated by reference herein.

FIELD OF THE INVENTION

The invention generally relates to endless tracks for providing tractionto off-road vehicles.

BACKGROUND

Certain off-road vehicles, such as agricultural vehicles (e.g.,tractors, harvesters, combines, etc.), construction vehicles (e.g.,loaders, bulldozers, excavators, etc.) forestry vehicles (e.g.,feller-bunchers, tree chippers, knuckleboom loaders, etc.) and otherindustrial vehicles, military vehicles (e.g., combat engineeringvehicles (CEVs), etc.), snowmobiles, and all-terrain vehicles (ATVs),may be equipped with elastomeric endless tracks which enhance theirtraction and floatation on soft, slippery and/or irregular grounds(e.g., soil, mud, sand, ice, snow, etc.) on which they operate.

Traction, floatation and other aspects relating to use and performanceof tracked vehicles depend on various factors, including the vehicles'tracks. For example, rigidity characteristics as well as resistance towear, damage or other deterioration of a track can have a significantinfluence on traction, floatation and other performance aspects of avehicle propelled by the track.

While track designs have evolved, there remains a need to improveelastomeric endless tracks for traction of vehicles.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a track fortraction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises an inner surface for facing thetrack-engaging assembly, a ground-engaging outer surface for engagingthe ground, and a plurality of traction projections projecting from theground-engaging outer surface. The track has an asymmetric rigidity suchthat the track is stiffer when subject to loading tending to bend thetrack in a given way than when subject to loading tending to bend thetrack in an opposite way.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises an inner surface for facing thetrack-engaging assembly, a ground-engaging outer surface for engagingthe ground, and a plurality of traction projections projecting from theground-engaging outer surface. A widthwise rigidity of the track whensubject to loading tending to bend the track inwardly is different fromthe widthwise rigidity of the track when subject to loading tending tobend the track outwardly.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises an inner surface for facing thetrack-engaging assembly, a ground-engaging outer surface for engagingthe ground, and a plurality of traction projections projecting from theground-engaging outer surface. A longitudinal rigidity of the track whensubject to loading tending to bend the track inwardly is different fromthe longitudinal rigidity of the track when subject to loading tendingto bend the track outwardly.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly and a ground-engaging outer surfacefor engaging the ground. The track comprises a plurality of tractionprojections projecting from the ground-engaging outer surface. Thecarcass has an asymmetric rigidity such that the carcass is stiffer whensubject to loading tending to bend the carcass in a given way than whensubject to loading tending to bend the carcass in an opposite way.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly and a ground-engaging outer surfacefor engaging the ground. The track comprises a plurality of tractionprojections projecting from the ground-engaging outer surface. Awidthwise rigidity of the carcass when subject to loading tending tobend the carcass inwardly is different from the widthwise rigidity ofthe carcass when subject to loading tending to bend the carcassoutwardly.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly and a ground-engaging outer surfacefor engaging the ground. The track comprises a plurality of tractionprojections projecting from the ground-engaging outer surface. Alongitudinal rigidity of the carcass when subject to loading tending tobend the carcass inwardly is different from the longitudinal rigidity ofthe carcass when subject to loading tending to bend the carcassoutwardly.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a plurality of wheels that includes adrive wheel for driving the track. The track is elastomeric to beflexible around the track-engaging assembly. The track comprises acarcass comprising an inner surface for facing the track-engagingassembly and a ground-engaging outer surface for engaging the ground.The track comprises a plurality of traction projections projecting fromthe ground-engaging outer surface. The carcass is bent in a widthwisedirection of the track and deformable in the widthwise direction of thetrack under loading from respective ones of the wheels.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly and a ground-engaging outer surfacefor engaging the ground. The track comprises a plurality of tractionprojections projecting from the ground-engaging outer surface. Thecarcass comprises an arrangement of movable zones and movementfacilitators disposed between the movable zones. The movable zones aremovable relative to one another as the track is driven around thetrack-engaging assembly.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising elastomeric material,an inner surface for facing the track-engaging assembly, and aground-engaging outer surface for engaging the ground. The trackcomprises a plurality of traction projections projecting from theground-engaging outer surface. The carcass comprises a first reinforcinglayer embedded in the elastomeric material between a neutral axis of thecarcass and the inner surface and a second reinforcing layer embedded inthe elastomeric material between the neutral axis of the carcass and theground-engaging outer surface and having a different stiffness in agiven direction of the track than the first reinforcing layer.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a plurality of wheels that includes adrive wheel for driving the track. The track is elastomeric to beflexible around the track-engaging assembly. The track comprises aninner surface for facing the track-engaging assembly, a ground-engagingouter surface for engaging the ground, and a plurality of tractionprojections projecting from the ground-engaging outer surface. The trackcomprises a plurality of transversal cables adjacent to one another,extending transversally to a longitudinal direction of the track, andarranged to be in tension under loading from respective ones of thewheels.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly, a ground-engaging outer surface forengaging the ground, elastomeric material, and a reinforcement layerembedded in the elastomeric material. The track comprises a plurality oftraction projections projecting from the ground-engaging outer surface.The carcass exhibits a variation of a density of the reinforcement layerin a widthwise direction of the track.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a plurality of wheels that includes adrive wheel for driving the track. The track is elastomeric to beflexible around the track-engaging assembly. The track comprises acarcass comprising an inner surface for facing the track-engagingassembly and a ground-engaging outer surface for engaging the ground.The track comprises a plurality of traction projections projecting fromthe ground-engaging outer surface. The inner surface comprises aplurality of aligners spaced from one another to align respective areasof the inner surface with respective ones of the wheels and opposemovement of the track relative to the respective ones of the wheels in awidthwise direction of the track.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly and a ground-engaging outer surfacefor engaging the ground. The track comprises a plurality of tractionprojections projecting from the ground-engaging outer surface. Thecarcass comprises a peripheral reinforcing layer adjacent to a peripheryof the carcass.

According to another aspect of the invention, there is provided a trackfor traction of an off-road vehicle. The track is mountable around atrack-engaging assembly comprising a drive wheel for driving the track.The track is elastomeric to be flexible around the track-engagingassembly. The track comprises a carcass comprising an inner surface forfacing the track-engaging assembly and a ground-engaging outer surfacefor engaging the ground. The track comprises a plurality of tractionprojections projecting from the ground-engaging outer surface. Thecarcass comprises a multitude of reinforcing fabric layers that arestacked in a thickness direction of the track.

These and other aspects of the invention will now become apparent tothose of ordinary skill in the art upon review of the followingdescription of embodiments of the invention in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of embodiments of the invention is providedbelow, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 shows an example of a tracked vehicle in accordance with anembodiment of the invention;

FIGS. 2 to 5 respectively show a outer plan view, a side view, an innerplan view, and a cross-sectional view of an example of a track of atrack system of the tracked vehicle;

FIG. 6 shows an example of a drive wheel of the track system;

FIGS. 7A and 7B show an example in which the track is easier to bendtransversally in a given way than in an opposite way in accordance withan embodiment of the invention;

FIGS. 8A and 8B show an example in which the track is easier to bendlongitudinally in a given way than in an opposite way in accordance withan embodiment of the invention;

FIGS. 9A and 9B show an example in which a carcass of the track iseasier to bend transversally in a given way than in an opposite way inaccordance with an embodiment of the invention;

FIGS. 10A and 10B show an example in which the carcass of the track iseasier to bend longitudinally in a given way than in an opposite way inaccordance with an embodiment of the invention;

FIGS. 11 to 13 show examples in which the carcass of the track ismanufactured bent in accordance with embodiments of the invention;

FIGS. 14 to 21 show examples in which the carcass of the track comprisesmovable zones in accordance with embodiments of the invention;

FIG. 22 shows an example in which the carcass of the track comprisesreinforcing layers of different stiffness in accordance with anembodiment of the invention;

FIGS. 23 to 30 show examples in which the carcass of the track comprisestransversal stiffening cables in accordance with embodiments of theinvention;

FIGS. 31, 38 and 39 show examples in which the carcass of the trackexhibits a widthwise variation of density of a reinforcing layerembedded in elastomeric material of the carcass in accordance withembodiments of the invention;

FIGS. 32 and 33 shows an example in which the track is self-aligning inaccordance with an embodiment of the invention;

FIGS. 34 and 35 show examples in which the carcass of the trackcomprises a peripheral reinforcing layer adjacent to its periphery inaccordance with embodiments of the invention;

FIGS. 36 and 37 show an example in which the carcass of the trackcomprises a multitude of reinforcing fabric layers in accordance with anembodiment of the invention; and

FIGS. 38 and 39 show other examples in which the carcass of the trackexhibits a widthwise variation of density of a reinforcing layerembedded in elastomeric material of the carcass in accordance with otherembodiments of the invention.

It is to be expressly understood that the description and drawings areonly for the purpose of illustrating certain embodiments of theinvention and are an aid for understanding. They are not intended to bea definition of the limits of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 shows an example of an off-road tracked vehicle 10 in accordancewith an embodiment of the invention. In this embodiment, the vehicle 10is a heavy-duty work vehicle for performing agricultural work,construction work or other industrial work, or military work. Moreparticularly, in this embodiment, the vehicle 10 is an agriculturalvehicle for performing agricultural work. Specifically, in this example,the agricultural vehicle 10 is a tractor. In other examples, theagricultural vehicle 10 may be a combine harvester, another type ofharvester, or any other type of agricultural vehicle.

The agricultural vehicle 10 comprises a frame 12, a powertrain 15, apair of track systems 16 ₁, 16 ₂, and an operator cabin 20, which enablean operator to move the agricultural vehicle 10 on the ground to performagricultural work, possibly using a work implement 18.

The powertrain 15 is configured for generating motive power andtransmitting motive power to the track systems 16 ₁, 16 ₂ to propel theagricultural vehicle 10 on the ground. To that end, the powertrain 13comprises a prime mover 14, which is a source of motive power thatcomprises one or more motors (e.g., an internal combustion engine, anelectric motor, etc.). For example, in this embodiment, the prime mover14 comprises an internal combustion engine. In other embodiments, theprime mover 14 may comprise another type of motor (e.g., an electricmotor) or a combination of different types of motor (e.g., an internalcombustion engine and an electric motor). The prime mover 14 is in adriving relationship with the track systems 16 ₁, 16 ₂. That is, thepowertrain 15 transmits motive power from the primer mover 14 to thetrack systems 16 ₁, 16 ₂ in order to drive (i.e., impart motion to) thetrack systems 16 ₁, 16 ₂.

The work implement 18 is used to perform agricultural work. For example,in some embodiments, the work implement 18 may be a combine head, acutter, a scraper, a tiller or any other type of agricultural workimplement.

The operator cabin 20 is where the operator sits and controls theagricultural vehicle 10. More particularly, the operator cabin 20comprises a set of controls that allow the operator to steer theagricultural vehicle 10 on the ground and operate the work implement 18.

The track systems 16 ₁, 16 ₂ engage the ground to propel theagricultural vehicle 10. The track system 16 ₁ is located on a givenlateral side of the vehicle 10, while the track system 16 ₂ (not shown)is located on an opposite lateral side of the vehicle 10. In thisembodiment, each track system 16 _(i) comprises a track-engagingassembly 21 and a track 22 disposed around the track-engaging assembly21. More particularly, in this embodiment, the track-engaging assembly21 comprises a plurality of wheels, including a drive wheel 24 and aplurality of idler wheels which includes a front idler wheel 26 and aplurality of roller wheels 28 ₁-28 ₆. The track system 16 _(i) alsocomprises a track frame 13 which supports various components of thetrack system 16 _(i), including the roller wheels 28 ₁-28 ₆. The tracksystem 16 _(i) has a longitudinal direction and a first longitudinal end57 and a second longitudinal end 59 that define a length of the tracksystem 16 _(i). The track system 16 _(i) has a widthwise direction and awidth that is defined by a width of the track 22. The track system 16_(i) also has a height direction that is normal to its longitudinaldirection and its widthwise direction.

The track 22 engages the ground to provide traction to the agriculturalvehicle 10. As further discussed below, in various embodiments, thetrack 22 may have various features to enhance its traction, itsfloatation, and/or other aspects relating to use and performance of thetrack system 16 _(i).

A length of the track 22 allows the track 22 to be mounted around thetrack-engaging assembly 21. In view of its closed configuration withoutends that allows it to be disposed and moved around the track-engagingassembly 21, the track 22 can be referred to as an “endless” track. Withadditional reference to FIGS. 2 to 5, the track 22 comprises an innerside 45, a ground-engaging outer side 47, and lateral edges 49 ₁, 49 ₂.The inner side 45 faces the wheels 24, 26, 28 ₁-28 ₆, while theground-engaging outer side 47 engages the ground. A top run 65 of thetrack 22 extends between the longitudinal ends 57, 59 of the tracksystem 16 _(i) and over the wheels 24, 26, 28 ₁-28 ₆, while a bottom run66 of the track 22 extends between the longitudinal ends 57, 59 of thetrack system 16 _(i) and under the wheels 24, 26, 28 ₁-28 ₆. The track22 has a longitudinal axis 19 which defines a longitudinal direction ofthe track 22 (i.e., a direction generally parallel to its longitudinalaxis) and transversal directions of the track 22 (i.e., directionstransverse to its longitudinal axis), including a widthwise direction ofthe track 22 (i.e., a lateral direction generally perpendicular to itslongitudinal axis). The track 22 has a thickness direction normal to itslongitudinal and widthwise directions.

The track 22 is elastomeric, i.e., comprises elastomeric material, to beflexible around the track-engaging assembly 21. The elastomeric materialof the track 22 can include any polymeric material with suitableelasticity. In this embodiment, the elastomeric material of the track 22includes rubber. Various rubber compounds may be used and, in somecases, different rubber compounds may be present in different areas ofthe track 22. In other embodiments, the elastomeric material of thetrack 22 may include another elastomer in addition to or instead ofrubber (e.g., polyurethane elastomer).

More particularly, the track 22 comprises an endless body 36 underlyingits inner side 45 and ground-engaging outer side 47. In view of itsunderlying nature, the body 36 will be referred to as a “carcass”. Thecarcass 36 is elastomeric in that it comprises elastomeric material 38which allows the carcass 36 to elastically change in shape and thus thetrack 22 to flex as it is in motion around the track-engaging assembly21. The carcass 36 comprises an inner surface 32 and a ground-engagingouter surface 31 that are opposite one another.

In this embodiment, the carcass 36 comprises a plurality ofreinforcements embedded in its elastomeric material 38. Thesereinforcements can take on various forms.

For example, in this embodiment, the carcass 36 comprises a layer ofreinforcing cables 37 ₁-37 _(M) that are adjacent to one another andextend generally in the longitudinal direction of the track 22 toenhance strength in tension of the track 22 along its longitudinaldirection. In this case, each of the reinforcing cables 37 ₁-37 _(M) isa cord including a plurality of strands (e.g., textile fibers ormetallic wires). In other cases, each of the reinforcing cables 37 ₁-37_(M) may be another type of cable and may be made of any materialsuitably flexible along the cable's longitudinal axis (e.g., fibers orwires of metal, plastic or composite material).

As another example, in this embodiment, the carcass 36 comprises a layerof reinforcing fabric 43. The reinforcing fabric 43 comprises thinpliable material made usually by weaving, felting, knitting,interlacing, or otherwise crossing natural or synthetic elongated fabricelements, such as fibers, filaments, strands and/or others, such thatsome elongated fabric elements extend transversally to the longitudinaldirection of the track 22 to have a reinforcing effect in a transversaldirection of the track 22. For instance, the reinforcing fabric 43 maycomprise a ply of reinforcing woven fibers (e.g., nylon fibers or othersynthetic fibers).

The carcass 36 has a thickness T_(c), measured from its inner surface 32to its ground-engaging outer surface 31, which is relatively large inthis embodiment. For example, in some embodiments, the thickness T_(c)of the carcass 36 may be at least than 20 mm, in some cases at least 25mm, in some cases at least 30 mm, in some cases at least 35 mm, and insome cases even more (e.g., 40 mm or more). The thickness T_(c) of thecarcass 36 may have any other suitable value in other embodiments.

The carcass 36 may be molded into shape in a molding process duringwhich the rubber 38 is cured. For example, in this embodiment, a moldmay be used to consolidate layers of rubber providing the rubber 38 ofthe carcass 36, the reinforcing cables 37 ₁-37 _(M) and the layer ofreinforcing fabric 43.

In this embodiment, the endless track 22 is a one-piece “jointless”track such that the carcass 36 is a one-piece jointless carcass. Inother embodiments, the endless track 22 may be a “jointed” track (i.e.,having at least one joint connecting adjacent parts of the track 22)such that the carcass 36 is a jointed carcass (i.e., which has adjacentparts connected by the at least one joint). For example, in someembodiments, the track 22 may comprise a plurality of track sectionsinterconnected to one another at a plurality of joints, in which caseeach of these track sections includes a respective part of the carcass36. In other embodiments, the endless track 22 may be a one-piece trackthat can be closed like a belt with connectors at both of itslongitudinal ends to form a joint.

The ground-engaging outer side 47 of the track 22 comprises theground-engaging outer surface 31 of the carcass 36 and a plurality oftraction projections 58 ₁-58 _(T) that project outwardly from theground-engaging outer surface 31 to form a tread pattern 40. Thetraction projections 58 ₁-58 _(T), which can be referred to as “tractionlugs”, may have any suitable shape (e.g., straight shapes, curvedshapes, shapes with straight parts and curved parts, etc.). In thisembodiment, each of the traction projection 58 ₁-58 _(T) is anelastomeric traction projection in that it comprises elastomericmaterial 41.

The traction projections 58 ₁-58 _(T) may be provided on theground-engaging outer side 47 in various ways. For example, in thisembodiment, the traction projections 58 ₁-58 _(T) are provided on theground-engaging outer side 47 by being molded with the carcass 36.

In this embodiment, the inner side 45 of the track 22 comprises theinner surface 32 of the carcass 36 and a plurality of inner projections48 ₁-48 _(N) that project inwardly from the inner surface 32 and arepositioned to contact at least some of the wheels 24, 26, 28 ₁-28 ₆ todo at least one of driving (i.e., imparting motion to) the track 22 andguiding the track 22. Since each of them is used to do at least one ofdriving the track 22 and guiding the track 22, the inner projections 48₁-48 _(N) can be referred to as “drive/guide projections” or“drive/guide lugs”. In some cases, a drive/guide lug 48 _(i) mayinteract with the drive wheel 24 to drive the track 22, in which casethe drive/guide lug 48 _(i) is a drive lug. In other cases, adrive/guide lug 48 _(i) may interact with a given one of the idlerwheels 26, 28 ₁-28 ₆ to guide the track 22 to maintain proper trackalignment and prevent de-tracking without being used to drive the track22, in which case the drive/guide lug 48 _(i) is a guide lug. In yetother cases, a drive/guide lug 48 _(i) may both (i) interact with thedrive wheel 24 to drive the track 22 and (ii) interact with a given oneof the idler wheels 26, 28 ₁-28 ₆ to guide the track 22, in which casethe drive/guide lug 48 _(i) is both a drive lug and a guide lug. In thisembodiment, each of the drive/guide lugs 48 ₁-48 _(N) is an elastomericdrive/guide lug in that it comprises elastomeric material 42.

Each drive/guide lug 48 _(i) has a front-to-rear dimension L_(L) in thelongitudinal direction of the track 22 and a side-to-side dimensionL_(W) in the widthwise direction of the track 22. In some cases, thefront-to-rear dimension L_(L) may be a width of the drive/guide lug 48_(i) while the side-to-side dimension L_(W) may be a length of thedrive/guide lug 48 _(i). In other cases, the front-to-rear dimensionL_(L) may be a length of the drive/guide lug 48 _(i) while theside-to-side dimension L_(W) may be a width of the drive/guide lug 48_(i). In yet other cases, the front-to-rear dimension L_(L) and theside-to-side dimension L_(W) may be substantially the same. Thedrive/guide lug 48 _(i) also has a height H.

The drive/guide lugs 48 ₁-48 _(N) may be provided on the inner side 45in various ways. For example, in this embodiment, the drive/guide lugs48 ₁-48 _(N) are provided on the inner side 45 by being molded with thecarcass 36.

The drive wheel 24 is rotatable by power derived from the prime mover 14to drive the track 22. That is, power generated by the prime mover 14and delivered over the powertrain 15 of the agricultural vehicle 10 canrotate a driven axle, which causes rotation of the drive wheel 24, whichin turn imparts motion of the track 22.

In this embodiment, with additional reference to FIG. 6, the drive wheel24 comprises a drive sprocket comprising a plurality of drive members 52₁-52 _(B) spaced apart along a circular path to engage the drive/guidelugs 48 ₁-48 _(N) of the track 22 in order to drive the track 22. Thedrive wheel 24 and the track 22 thus implement a “positive drive”system. The drive wheel 24 may be configured in various other ways inother embodiments. For example, in other embodiments, instead of beingdrive bars, the drive members 52 ₁-52 _(B) may be drive teeth that aredistributed circumferentially along the drive wheel 24 or any other typeof drive members. As another example, in embodiments where the track 22comprises recesses or holes, the drive wheel 24 may have teeth thatenter these recesses or holes in order to drive the track 22. As yetanother example, in some embodiments, the drive wheel 24 mayfrictionally engage the inner side 45 of the track 22 in order tofrictionally drive the track 22 (i.e., the drive wheel 24 and the track22 may implement a “friction drive” system).

The front idler wheel 26 and the roller wheels 28 ₁-28 ₆ are not drivenby power supplied by the prime mover 14, but are rather used to do atleast one of supporting part of a weight of the agricultural vehicle 10on the ground via the track 22, guiding the track 22 as it is driven bythe drive wheel 24, and tensioning the track 22. More particularly, inthis embodiment, the front idler wheel 26 is a leading idler wheel whichmaintains the track 22 in tension and helps to support part of theweight of the agricultural vehicle 10 on the ground via the track 22.The roller wheels 28 ₁-28 ₆ roll on respective ones of a plurality ofrolling paths 33 ₁, 33 ₂ of the inner surface 32 of the carcass 36 alongthe bottom run 66 of the track 22 to apply the bottom run 66 on theground. Each of the rolling paths 33 ₁, 33 ₂ extends adjacent to thedrive/guide lugs 48 ₁-48 _(N) to allow these lugs to guide motion of thetrack 22 around the track-engaging assembly 21. In this case, as theyare located between frontmost and rearmost ones of the wheels of thetrack assembly 16 _(i), the roller wheels 28 ₁-28 ₆ can be referred toas “mid-rollers”.

Various considerations are important when it comes to use andperformance of the track system 16 _(i), including its track 22.Notably, in various embodiments, the track 22, including its carcass 36,may have various features to enhance its rigidity characteristics, itsresistance to wear or other deterioration, and/or other characteristicsin order to improve its traction, its floatation, and/or other aspectsrelating to use and performance of the track system 16 _(i). Examples ofsuch features will now be discussed.

1. Enhanced Rigidity Characteristics

In some embodiments, the track 22 may have rigidity (i.e., stiffness)characteristics to provide better load distribution, reduce powerconsumption, and/or enhance other aspects of the track system 16 _(i).For instance, these rigidity characteristics may relate to (1) alongitudinal rigidity of the track 22, i.e., a rigidity of the track 22in its longitudinal direction which refers to the track's resistance tobending about an axis parallel to its widthwise direction, and/or (2) awidthwise rigidity of the track 22, i.e., a rigidity of the track 22 inits widthwise direction which refers to the track's resistance tobending about an axis parallel to its longitudinal direction.

For example, in some embodiments, the widthwise rigidity of the track 22may be such that, although it may be flexible in its widthwise direction(e.g., due to its elastomeric nature), the track 22 can be sufficientlyrigid in its widthwise direction to properly distribute loading on thetrack 22 for floatation and traction (e.g., by tending to avoid asituation in which most of the loading on the track 22 is distributedonly under and near the mid-rollers 28 ₁-28 ₆ with little or no loadingbeing distributed on parts of the track 22 between the mid-rollers 28₁-28 ₆ and the track's lateral edges 49 ₁, 49 ₂).

As another example, in some embodiments, the longitudinal rigidity ofthe track 22 may be such that, although it can flex in its longitudinaldirection to move around the track-engaging assembly 21 (e.g., to reducepower consumed to bend it as it turns about the idler wheel 26 and thedrive wheel 24), the track 22 can be sufficiently rigid in itslongitudinal direction to help maintain a generally straight shape ofthe bottom run 66 of the track 22 for proper traction).

The rigidity characteristics of the track 22 depend on rigiditycharacteristics of the carcass 36, including (1) a longitudinal rigidityof the carcass 36, i.e., a rigidity of the carcass 36 in the track'slongitudinal direction which refers to the carcass's resistance tobending about an axis parallel to the track's widthwise direction, and(2) a widthwise rigidity of the carcass 36, i.e., a rigidity of thecarcass 36 in the track's widthwise direction which refers to thecarcass's resistance to bending about an axis parallel to the track'slongitudinal direction.

1.1 Asymmetric Rigidity

In some embodiments, the track 22 may have an asymmetric rigidity suchthat it is easier to bend in a given way than in an opposite way, i.e.,it is stiffer when subject to loading tending to bend it in a given waythan when subject to loading tending to bend it in an opposite way.

For example, in some embodiments, as shown in FIGS. 7A and 7B, thewidthwise rigidity of the track 22 when subject to loading tending tobend the track 22 inwardly (i.e., bend the track 22 such that itslateral edges 49 ₁, 49 ₂ move in an inward direction oriented from itsground-engaging outer side 47 towards its inner side 45 as shown in FIG.7A) may be different from the widthwise rigidity of the track 22 whensubject to loading tending to bend the track 22 outwardly (i.e., bendthe track 22 such that its lateral edges 49 ₁, 49 ₂ move in an outwarddirection oriented from its inner side 45 towards its ground-engagingouter side 47 as shown in FIG. 7B).

In some cases, the widthwise rigidity of the track 22 when subject toloading tending to bend the track 22 inwardly may be greater than thewidthwise rigidity of the track 22 when subject to loading tending tobend the track 22 outwardly. This may help the track 22 to have a largewidthwise extent that is relatively rigid transversally against loadingof the mid-rollers 28 ₁-28 ₆ to improve traction and floatation. Inother cases, the widthwise rigidity of the track 22 when subject toloading tending to bend the track 22 inwardly may be less than thewidthwise rigidity of the track 22 when subject to loading tending tobend the track 22 outwardly (e.g., in situations where the width of thetrack 22 is greater than a row crop spacing in which the track 22 isused, or to facilitate turning).

As another example, in some embodiments, as shown in FIGS. 8A and 8B,the longitudinal rigidity of the track 22 when subject to loadingtending to bend the track 22 inwardly (i.e., bend the track 22 such thata flat area of the inner surface 32 of the carcass 36 bends in an inwarddirection and becomes generally concave as shown in FIG. 8A) may bedifferent from the longitudinal rigidity of the track 22 when subject toloading tending to bend the track 22 outwardly (i.e., bend the track 22such that a flat area of the inner surface 32 of the carcass 36 bends inan outward direction and becomes generally convex as shown in FIG. 8 b).

In some cases, the longitudinal rigidity of the track 22 when subject toloading tending to bend the track 22 inwardly may be less than thelongitudinal rigidity of the track 22 when subject to loading tending tobend the track 22 outwardly. This may facilitate bending of the track 22as it turns about the idler wheel 26 and the drive wheel 24, which mayreduce power consumption to drive the track 22. In other cases, thelongitudinal rigidity of the track 22 when subject to loading tending tobend the track 22 inwardly may be greater than the longitudinal rigidityof the track 22 when subject to loading tending to bend the trackoutwardly (e.g., to facilitate conformance to obstacles on the ground orother terrain variations).

To observe the widthwise rigidity and/or the longitudinal rigidity ofthe track 22, a test can be performed to (1) subject the track 22 to abending load having a predetermined magnitude and tending to bend thetrack 22 in a given way (i.e., inwardly or outwardly) and measure adeflection of the track 22 and (2) subject the track 22 to a bendingload having the predetermined magnitude and tending to bend the track 22in an opposite way (i.e., outwardly or inwardly) and measure adeflection of the track 22. If the deflection of the track 22 whensubjected to the bending load tending to bent the track 22 in the givenway is substantially different from (e.g., at least 10% greater or lowerthan, in some cases at least 15% greater or lower than, and in somecases at least 20% greater or lower than) the deflection of the track 22when subjected to the bending load tending to bend the track 22 in theopposite way, the track 22 is deemed to have an asymmetric stiffnesswith respect to bending in these two ways.

Since the rigidity characteristics of the track 22 depend on therigidity characteristics of the carcass 36, in some embodiments, thecarcass 36 may have an asymmetric rigidity such that it is easier tobend in a given way than in an opposite way, i.e., it is stiffer whensubject to loading tending to bend it in a given way than when subjectto loading tending to bend it in an opposite way.

For example, in some embodiments, as shown in FIGS. 9A and 9B, thewidthwise rigidity of the carcass 36 when subject to loading tending tobend the carcass 36 inwardly (i.e., bend the carcass 36 such that thelateral edges 49 ₁, 49 ₂ of the track 22 move in an inward directionoriented from its ground-engaging outer surface 31 towards its innersurface 32 as shown in FIG. 9A) may be different from the widthwiserigidity of the carcass 36 when subject to loading tending to bend thecarcass 36 outwardly (i.e., bend the carcass 36 such that the lateraledges 49 ₁, 49 ₂ of the track 22 move in an outward direction orientedfrom its inner surface 32 towards its ground-engaging outer surface 31as shown in FIG. 9B).

In some cases, the widthwise rigidity of the carcass 36 when subject toloading tending to bend the carcass 36 inwardly may be greater than thewidthwise rigidity of the carcass 36 when subject to loading tending tobend the carcass 36 outwardly. In other cases, the widthwise rigidity ofthe carcass 36 when subject to loading tending to bend the carcass 36inwardly may be less than the widthwise rigidity of the carcass 36 whensubject to loading tending to bend the carcass 36 outwardly.

As another example, in some embodiments, as shown in FIGS. 10A and 10B,the longitudinal rigidity of the carcass 36 when subject to loadingtending to bend the carcass 36 inwardly (i.e., bend the carcass 36 suchthat a flat area of the inner surface 32 of the carcass 36 bends in aninward direction and becomes generally concave as shown in FIG. 10A) maybe different from the longitudinal rigidity of the carcass 36 whensubject to loading tending to bend the carcass 36 outwardly (i.e., bendthe carcass 36 such that a flat area of the inner surface 32 of thecarcass 36 bends in an outward direction and becomes generally convex asshown in FIG. 10B).

In some cases, the longitudinal rigidity of the carcass 36 when subjectto loading tending to bend the carcass 36 inwardly may be less than thelongitudinal rigidity of the carcass 36 when subject to loading tendingto bend the carcass 36 outwardly. In other cases, the longitudinalrigidity of the carcass 36 when subject to loading tending to bend thecarcass 36 inwardly may be greater than the longitudinal rigidity of thecarcass 36 when subject to loading tending to bend the carcass 36outwardly.

To observe the widthwise rigidity and/or the longitudinal rigidity ofthe carcass 36 (without influence from a remainder of the track 22), atest can be performed to: (1) isolate the carcass 36 from a remainder ofthe track 22 (e.g., by scraping, cutting or otherwise removing thetraction projections 58 ₁-58 _(T) and the drive/guide lugs 48 ₁-48 _(N),or by producing the carcass 36 without the traction projections 58 ₁-58_(T) and the drive/guide lugs 48 ₁-48 _(N)); (2) subject the carcass 36to a bending load having a predetermined magnitude and tending to bendthe carcass 36 in a given way (i.e., inwardly or outwardly) and measurea deflection of the carcass 36; (3) subject the carcass 36 to a bendingload having the predetermined magnitude and tending to bend the carcass36 in an opposite way (i.e., outwardly or inwardly) and measure adeflection of the carcass 36. If the deflection of the carcass 36 whensubjected to the bending load tending to bent the carcass 36 in thegiven way is substantially different from (e.g., at least 10% greater orlower than, in some cases at least 15% greater or lower than, and insome cases at least 20% greater or lower than) the deflection of thecarcass 36 when subjected to the bending load tending to bend thecarcass 36 in the opposite way, the carcass 36 is deemed to have anasymmetric stiffness with respect to bending in these two ways.

1.1.1 Bent Carcass Formed During Manufacturing

In some embodiments, as shown in FIG. 11, the carcass 36 of the track 22may be manufactured such that the carcass 36 is bent (i.e., non-planar)in the widthwise direction of the track 22 and deformable (i.e.,changeable in shape) in the widthwise direction of the track 22 underloading from respective ones of the wheels 24, 26, 28 ₁-28 ₆. That is, across-section of the carcass 36 (normal to the longitudinal axis 19 ofthe track 22) has a bent shape imparted during manufacturing of thetrack 22 and acquires a different shape when loaded by respective onesof the wheels 24, 26, 28 ₁-28 ₆. This different shape of thecross-section of the carcass 36 may provide better load distributiononto the ground. For instance, this different shape of the cross-sectionof the carcass 36 may result in the track 22 having a widerground-contacting area and being stiffer in its widthwise direction dueto an increased widthwise tension induced in its ground-engaging outerside 47. In some cases, the cross-section of the carcass 36 may regainits bent shape when no longer loaded by respective ones of the wheels24, 26, 28 ₁-28 ₆ (i.e., a spring-like effect) such that its deformationis elastic.

For example, in this embodiment, with additional reference to FIG. 12,the carcass 36 flattens in the widthwise direction of the track 22 underloading from the mid-rollers 28 ₁-28 ₆. The cross-section of the carcass36 thus acquires a flatter shape (i.e., a shape that is more flat thanthe bent shape) when loaded by the mid-rollers 28 ₁-28 ₆.

The carcass 36 may be bent in the widthwise direction of the track 22 bybeing curved and/or angular (i.e., having at least one angle) in thetrack's widthwise direction. The bent shape of the cross-section of thecarcass 36 is thus curved and/or angular, i.e., it comprises a curvedportion and/or an angular portion, between the track's lateral edges 49₁, 49 ₂. The cross-section of the carcass 36 is thereforenonrectangular.

In this embodiment, the carcass 36 is bent in the widthwise direction ofthe track 22 such that its inner surface 32 is generally convex and itsground-engaging outer surface 31 is generally concave. Under loadingfrom the mid-rollers 28 ₁-28 ₆ on the rolling paths 33 ₁, 33 ₂, thecarcass 36 flattens such that its inner surface 32 and itsground-engaging outer surface 31 become flatter. This flattening of thecarcass 36 generates an increased tension in the ground-engaging outerside 47 of the track 22, which, along with a resulting widerground-contacting area, may help to better distribute loading onto theground.

More particularly, in this embodiment, the carcass 36 is bent in thewidthwise direction of the track 22 by being curved in that widthwisedirection. A radius of curvature R of the carcass 36 in the track'swidthwise direction may have any suitable value. For example, in someembodiments, the radius of curvature R of the carcass 36 may be greaterthan the width of the track 22, such as in some cases at least twice thewidth of the track 22, in some cases at least five times of the width ofthe track 22, in some cases at least ten times of the width of the track22, in some cases at least 20 times the width of the track 22, and insome cases even more (e.g., 40 times or more the width of the track 22).For instance, in some embodiments, the radius of curvature R of thecarcass 36 in the track's widthwise direction may be between 100 inchesand 2000 inches, in some cases between 150 inches and 1800 inches, andin some cases between 200 inches and 1600 inches. The radius ofcurvature R of the carcass 36 may have any other value in otherembodiments.

The carcass 36 may be bent in the widthwise direction of the track 22 invarious other ways in other embodiments. For example, in someembodiments, instead of or in addition to being curved, thecross-section of the carcass 36 may comprise angular portions to makethe carcass's inner surface 32 generally convex and the carcass'sground-engaging outer surface 31 generally concave. FIG. 13 shows anembodiment in which the cross-section of the carcass 36 comprisesangular portions 50 ₁-50 ₄ each defining a bend angle α between adjacentflat areas of the inner surface 32 of the carcass 36. For instance, invarious examples of implementation, the bend angle α may be at least 2°,in some cases at least 5°, in some cases at least 10°, and in some caseseven more (e.g., 15° or more). The bend angle α may have any other valuein other embodiments.

While in embodiments considered above the cross-section of the carcass36 deforms in the widthwise direction of the track 22 under loading fromthe mid-rollers 28 ₁-28 ₆, in other embodiments, the cross-section ofthe carcass 36 may be deformable in the widthwise direction of the track22 to provide better load-distribution onto the ground under loadingfrom other track-engaging elements (e.g., slide rails) of thetrack-engaging assembly 21 that engage the bottom run 66 of the track22.

1.1.2 Carcass Comprising Movable Zones

In some embodiments, as shown in FIGS. 14 and 15, the carcass 36 maycomprise an arrangement of movable zones 62 ₁-62 _(M) that are movablerelative to one another as the track 22 is driven around thetrack-engaging assembly 21. This relative movement is such that thearrangement of movable zones 62 ₁-62 _(M) is expandable and contractibleas the track 22 is driven around the track-engaging assembly 21 and thecarcass 36 is easier to bend in a given way than in an opposite way.More particularly, in this embodiment, the movable zones 62 ₁-62 _(M)can move relative to one another such that the longitudinal rigidity ofthe carcass 36 when subject to loading tending to bend the carcass 36inwardly is less than the longitudinal rigidity of the carcass 36 whensubject to loading tending to bend the carcass 36 outwardly. This makesit easier to bend the carcass 36 as it turns about the idler wheel 26and the drive wheel 24, thereby reducing power consumption to drive thetrack 22, while helping to maintain the bottom run 66 of the track 22generally straight for proper traction.

Movement facilitators 63 ₁-63 _(F) are disposed between adjacent ones ofthe movable zones 62 ₁-62 _(M) to facilitate movement of the movablezones 62 ₁-62 _(M) relative to one another. Adjacent movable zones 62_(i), 62 _(j) are easier to move relative to one another in a given waythan in an opposite way. For example, in this embodiment, the adjacentmovable zones 62 _(i), 62 _(j) are easier to move away from one anotherthan towards one another. In other embodiments, the adjacent movablezones 62 _(i), 62 _(j) may be easier to move towards one another thanaway from one another.

In this embodiment, the movable zones 62 ₁-62 _(M) are movable blocksand the movement facilitators 63 ₁-63 _(F) are gaps between the movableblocks 62 ₁-62 _(M). More particularly, in this embodiment, each of themovable blocks 62 ₁-62 _(M) and the gaps 63 ₁-63 _(F) extendstransversally for at least a substantial portion, such as at least amajority, in this case, an entirety, of the width of the track 22. A gap63 _(i) between adjacent movable zones 62 _(i), 62 _(j) is larger whenadjacent movable zones 62 _(i), 62 _(j) are located around the drivewheel 24 or the idler wheel 26 then when the adjacent movable zones 62_(i), 62 _(j) are located in the bottom run 66 of the track 22. Forinstance, in some cases, the gap 63 _(i) between the adjacent movablezones 62 _(i), 62 _(j) may be closed when the adjacent movable zones 62_(i), 62 _(j) are located in the bottom run 66 of the track 22 such thatthe adjacent movable 62 _(i), 62 _(j) are contiguous (i.e., contact oneanother). In other examples, the gap 63 _(i) between the adjacentmovable zones 62 _(i), 62 _(j) may be smaller without being closed whenthe adjacent movable zones 62 _(i), 62; are located in the bottom run 66of the track 22 such that the adjacent movable zones 62 _(i), 62 _(j)are noncontiguous (i.e., do not contact one another).

The movable zones 62 ₁-62 _(M) are interconnected such that they remaintogether as a unit. In this embodiment, an elastomeric layer 67 of thecarcass 36 interconnects the movable zones 62 ₁-62 _(M). Moreparticularly, in this embodiment, the elastomeric layer 67 extendsbetween the movable zones 62 ₁-62 _(M) and the inner surface 32 of thecarcass 36. Also, in this embodiment, as shown in FIG. 16,reinforcements of the carcass 36, namely the reinforcing cables 37 ₁-37_(M) and the reinforcing fabric 43, are embedded in the elastomericlayer 67.

In this embodiment, the movable zones 62 ₁-62 _(M) are exposed such thatthey are visible. More particularly, in this embodiment, the movablezones 62 ₁-62 _(M) comprise respective portions 56 ₁-56 _(M) of theground-engaging outer surface 31 of the carcass 36 from which projectcertain ones of the traction projections 58 ₁-58 _(T). Since in thisexample a traction projection 58 _(x) (shown in dotted outline in FIG.15) extends obliquely to the longitudinal direction of the track 22, twoor more portions 55 ₁-55 _(P) of the traction projection 58 _(x) mayproject from adjacent ones of the movable zones 62 ₁-62 _(M) such that,when these adjacent movable zones are located in the bottom run 66 ofthe track 22, the two or more portions 55 ₁-55 _(P) of the tractionprojection 58 _(x) are aligned with one another to form the tractionprojection 58 _(x). For instance, in some cases, the two or moreportions 55 ₁-55 _(P) of the traction projection 58 _(x) may becomecontiguous when these adjacent movable zone are located in the bottomrun 66 of the track 22. In other embodiments, the movable zones 62 ₁-62_(M), rather than be exposed, may be hidden internally within thecarcass 36 (e.g., the ground-engaging outer surface 31 of the carcass 36may be formed by a layer of elastic material covers the movable zones 62₁-62 _(M) and the movement facilitators 63 ₁-63 _(F)).

The movable zones 62 ₁-62 _(M) may be provided in various ways. Forexample, in some embodiments, the movable zones 62 ₁-62 _(M) may bemolded by forming the gaps 63 ₁-63 _(F) while molding the track 22. Inother embodiments, the movable zones 62 ₁-62 _(M) may be formed aftermolding of the track 22 (e.g., by cutting, carving or otherwise removingrubber at locations where the gaps 63 ₁-63 _(F) are to be formed).

The arrangement of movable zones 62 ₁-62 _(M) may be configured invarious other ways in other embodiments.

For example, in some embodiments, one or more of the reinforcements ofthe carcass 36, such as the reinforcing cables 37 ₁-37 _(M) and/or thereinforcing fabric 43, may be embedded in the movable zones 62 ₁-62 _(M)and move in relation to the movable zones 62 ₁-62 _(M) when these zonesmove relative to one another. For instance, as shown in FIG. 17, in someembodiments, a movable zone 62 _(x) may comprise a channel 68 allowingmovement of the reinforcing cables 37 ₁-37 _(M) relative to that zone.The channel 68 may include a lining (e.g., a sleeve) in which thereinforcing cables 37 ₁-37 _(M) can slide relative to the movable zone62 _(x).

As another example, in some embodiments, the movement facilitators 63₁-63 _(F) may be other than gaps. For instance, as shown in FIGS. 18 and19, in some embodiments, a movement facilitator 63 _(i) may compriseelastic material 69 that interconnects adjacent movable zones 62 _(i),62 _(i) and has a greater elasticity, i.e., a lower elastic modulus,than elastomeric material 70 of the adjacent movable zones 62 _(i), 62_(j) such that the elastic material 69 stretches to allow movement ofthe adjacent movable zones 62 _(i), 62 _(i) relative to one another. Forexample, in some embodiments, a ratio of an elastic modulus of theelastic material 69 of the movement facilitator 63 _(i) and an elasticmodulus of the elastomeric material 70 of the adjacent movable zones 62_(i), 62 _(i) may be no more than 0.9, in some cases no more than 0.8,in some cases no more than 0.7, and in some cases even less (e.g., nomore than 0.5). In some cases, the elastic material 69 may beelastomeric material (e.g., rubber such as sponge rubber or foam rubberproduced with a blowing agent or other foaming agent) that is moldedwith the elastomeric material 70 of the adjacent movable zones 62 _(i),62 _(j) (e.g., by placing the elastic material 69 between theelastomeric material 70 of the adjacent movable zones 62 _(i), 62 _(j)in a mold and curing them together). The elastic material 69 may be anyother suitable material in other cases (e.g., another type of foam, suchas a nonelastomeric foam). In other embodiments, instead of or inaddition to having a greater elasticity to stretch, the elastic material69 may have a greater compressibility than the elastomeric material 70of the adjacent movable zones 62 _(i), 62 _(j) such that the elasticmaterial 69 compresses to allow movement of the adjacent movable zones62 _(i), 62 _(j) relative to one another.

As yet another example, in some embodiments, instead of or in additionto modulating the longitudinal rigidity of the track 22, the arrangementof movable zones 62 ₁-62 _(M) may modulate the widthwise rigidity of thetrack 22. For instance, in some embodiments, as shown in FIG. 20, themovable zones 62 ₁-62 _(M) may extend along at least a substantialportion, such as at least a majority (e.g., an entirety), of the lengthof the track 22 and be moveable relative to one another such that thewidthwise rigidity of the carcass 36 when subject to loading tending tobend the carcass 36 inwardly is different from the widthwise rigidity ofthe carcass 36 when subject to loading tending to bend the carcass 36outwardly. In other embodiments, as shown in FIG. 21, the arrangement ofmovable zones 62 ₁-62 _(M) may be an array distributed in thelongitudinal and widthwise directions of the track 22 such that (i) thelongitudinal rigidity of the carcass 36 when subject to loading tendingto bend the carcass 36 inwardly is different from the longitudinalrigidity of the carcass 36 when subject to loading tending to bend thecarcass 36 outwardly and (ii) the widthwise rigidity of the carcass 36when subject to loading tending to bend the carcass 36 inwardly isdifferent from the widthwise rigidity of the carcass 36 when subject toloading tending to bend the carcass 36 outwardly.

1.1.3 Carcass Comprising Reinforcing Layers of Different Stiffness

In some embodiments, as shown in FIG. 22, the carcass 36 of the track 22may comprise a plurality of reinforcing layers 71 ₁, 71 ₂ of differentstiffness that are respectively embedded in the rubber 38 between aneutral axis 72 of the carcass 36 and each of the inner surface 32 andthe ground-engaging outer surface 31 of the carcass 36 such that thecarcass 36 is easier to bend in a given way than in an opposite way.

In this embodiment, the reinforcing layer 71 ₁ is embedded in the rubber38 between the neutral axis 72 of the carcass 36 and the inner surface32 of the carcass 36, while the reinforcing layer 71 ₂ is embedded inthe rubber 38 between the neutral axis 72 of the carcass 36 and theground-engaging outer surface 31 of the carcass 36 and has a differentstiffness in the widthwise direction of the track 22 than thereinforcing layer 71 ₁ such that the widthwise rigidity of the carcass36 when subject to loading tending to bend the carcass 36 inwardly isdifferent from the widthwise rigidity of the carcass 36 when subject toloading tending to bend the carcass 36 outwardly. In this example, thewidthwise rigidity of the carcass 36 when subject to loading tending tobend the carcass 36 inwardly is greater than the widthwise rigidity ofthe carcass 36 when subject to loading tending to bend the carcass 36outwardly.

More particularly, in this embodiment, the reinforcing layer 71 ₁ isstiffer in the widthwise direction of the track 22 than the reinforcinglayer 71 ₂. In this example, the reinforcing layer 71 ₁ is a non-textilereinforcing layer, while the reinforcing layer 71 ₂ is a textilereinforcing layer. More specifically, in this example, the reinforcinglayer 71 ₁ is a layer of reinforcing cables extending generally parallelto one another in the widthwise direction of the track 22 and thereinforcing layer 71 ₂ is a layer of reinforcing fabric. In this case,the reinforcing cables of the layer 71 ₁ are metallic cables and thelayer of reinforcing fabric 71 ₂ comprises a ply of reinforcing wovenfibers (e.g., nylon fibers or other synthetic fibers).

The reinforcing layers 71 ₁, 71 ₂ may be arranged in any suitable mannerwithin the carcass 36. In this embodiment, the reinforcing layer 71 ₁ islocated closer to the inner surface 32 than to the neutral axis 72 ofthe carcass 36 in the thickness direction of the track 22, and thereinforcing layer 71 ₂ is located closer to the ground-engaging outersurface 31 than to the neutral axis 72 of the carcass 36 in thethickness direction of the track 22. In some examples, the reinforcinglayers 71 ₁, 71 ₂ may be farthest apart from one another and farthestaway from the neutral axis 72 as possible. In other embodiments, thereinforcing layer 71 ₁ may be located closer to or as close to theneutral axis 72 of the carcass 36 than to the inner surface 32 in thethickness direction of the track 22, and/or the reinforcing layer 71 ₂may be located closer to or as close to the ground-engaging outersurface 31 than to the neutral axis 72 of the carcass 36 in thethickness direction of the track 22.

The reinforcing layers 71 ₁, 71 ₂ may be implemented in any othersuitable way in other embodiments. For example, in other embodiments,the reinforcing layer 71 ₁ may be a sheet (e.g. a metallic or polymericsheet) or a mesh (e.g., a metallic mesh or sheet) that is more rigid inthe widthwise direction of the track 22 than the reinforcing layer 71 ₁.As another example, in other embodiments, both of the reinforcing layers71 ₁, 71 ₂ may be textile reinforcing layers. As yet another example,each of the reinforcing layers 71 ₁, 71 ₂ may have a resistance totension different from a resistance to compression such that the carcass36 is easier to bend in a given way than in an opposite way.

1.2 Transversal Stiffening Cables

In some embodiments, as shown in FIGS. 23 to 25, the track 22 maycomprise a plurality of transversal cables 61 ₁-61 _(C) that areadjacent to one another and extend transversally to the longitudinaldirection of the track 22 to enhance the widthwise rigidity of the track22. The transversal cables 61 ₁-61 _(C) are arranged such that they arein tension under loading of the mid-rollers 28 ₁-28 ₆ and thusdistribute load over a greater extent in the widthwise direction of thetrack 22.

In this embodiment, each of the transversal cables 61 ₁-61 _(C) isgenerally straight over at least a majority, in this example anentirety, of its length when not loaded by the mid-rollers 28 ₁-28 ₆.Under loading of the mid-rollers 28 ₁-28 ₆, as shown in FIG. 26, thetransversal cables 61 ₁-61 _(C) bend such that they become concavetowards the inner side 45 of the track 22. This creates a tensioningeffect (e.g., localized tensions) in the transversal cables 61 ₁-61 _(C)that increases the widthwise rigidity of the track 22.

In other embodiments, as shown in FIG. 27, each of the transversalcables 61 ₁-61 _(C) may be uneven (i.e., non-straight) over its lengthwhen not loaded by the mid-rollers 28 ₁-28 ₆. Under loading of themid-rollers 28 ₁-28 ₆, as shown in FIG. 28, the transversal cables 61₁-61 _(C) bend and undergo a tensioning effect (e.g., localizedtensions) that increases the widthwise rigidity of the track 22.

More particularly, in this embodiment, each transversal cable 61 _(i) iswavy. Specifically, in this embodiments, segments 34 ₁, 34 ₃ of thetransversal cable 61 beneath the rolling paths 33 ₁, 33 ₂ of the innerside 45 of the track 22 extend closer to the inner surface 32 of thecarcass 36 than a segment 34 ₂ of the transversal cable 61 _(i) that isbetween the rolling paths 33 ₁, 33 ₂, which in this case extends closerto the ground-engaging outer surface 31 of the carcass 36. Under loadingof the mid-rollers 28 ₁-28 ₆, as shown in FIG. 28, the segments 34 ₁, 34₃ of the transversal cable 61 _(i) tend to deflect downwardly and thetransversal cable 61 _(i) undergoes a tensioning effect that increasesthe widthwise rigidity of the track 22.

In this example, the segments 34 ₁, 34 ₃ of the transversal cable 61_(i) are convex towards the inner side 45 of the track 22, while thesegment 34 ₂ of the transversal cable 61 _(i) is concave towards theinner side 45 of the track 22. In this case, this waviness of thetransversal cable 61 _(i), including this convexity and concavity of itssegments 34 ₁-34 ₃, is achieved by the transversal cable 61 _(i) beingcurved. In other cases, this waviness of the transversal cable 61 _(i),including this convexity and concavity of its segments 34 ₁-34 ₃, may beachieved by the transversal cable 61 _(i) having angular portions or acombination of angular and curved portions.

Any other wavy configuration of the transversal cable 61 _(i) may beused in other embodiments. For example, in other embodiments, thetransversal cable 61 _(i) may have a wavy configuration opposite to thatshown in FIG. 27 such that the segments 34 ₁, 34 ₃ of the transversalcable 61 _(i) beneath the rolling paths 33 ₁, 33 ₂ of the inner side 45of the track 22 extend closer to the ground-engaging outer surface 31 ofthe carcass 36 than the segment 34 ₂ of the transversal cable 61 _(i)that is between the rolling paths 33 ₁, 33 ₂, which may extend closer tothe inner surface 32 of the carcass 36.

In embodiments considered above, the carcass 36 of the track 22 isgenerally straight in the widthwise direction of the track 22. In otherembodiments, as shown in FIG. 29, the carcass 36 of the track 22 may bemanufactured such that the carcass 36 is bent in the widthwise directionof the track 22 and deformable in the widthwise direction of the track22 under loading from the mid-rollers 28 ₁-28 ₆, as discussed previouslyin section 1.1.1, and the transversal cables 61 ₁-61 _(C) are unevensuch that they also change in shape under loading from the mid-rollers28 ₁-28 ₆. For example, in this embodiment, the carcass 36 is bent inthe widthwise direction of the track 22 such that its inner surface 32is convex and its ground-engaging outer surface 31 is concave and thetransversal cables 61 ₁-61 _(C) are concave towards the ground-engagingouter surface 31. Under loading from the mid-rollers 28 ₁-28 ₆ on therolling paths 33 ₁, 33 ₂, the carcass 36 flattens such that its innersurface 32 and its ground-engaging outer surface 31 become flatter andthe transversal cables 61 ₁-61 _(C) also become flatter, therebyincreasing the widthwise rigidity of the track 22.

The transversal cables 61 ₁-61 _(C) may be implemented in various ways.For example, in this embodiment, each of the transversal cables 61 ₁-61_(C) is a cord including a plurality of strands (e.g., metallic wires ortextile fibers). In this case, each of the transversal cables 61 ₁-61_(C) is a metallic cable For instance, in some examples, each metalliccable may be a steel cable having any suitable diameter (e.g., adiameter of at least 1.5 mm). In other embodiments, each of thetransversal cables 61 ₁-61 _(C) may be another type of cable and may bemade of any material suitably flexible along the cable's longitudinalaxis (e.g., plastic or composite material).

In this embodiment, respective ones of the transversal cables 61 ₁-61_(C) are separate and independent from one another (i.e., unconnectedother than by elastomeric material of the track 22). In otherembodiments, as shown in FIG. 30, respective ones of the transversalcables 61 ₁-61 _(C) may be constituted by a single continuous cablelength 64 turning in a serpentine way such that there is a turn of thesingle continuous cable length 64 between adjacent ones of thetransversal cables 61 ₁-61 _(C).

The layer of transversal cables 61 ₁-61 _(C) may be implemented invarious other ways in other embodiments.

1.3 Variation of Reinforcement Density

In some embodiments, as shown in FIG. 31, the carcass 36 may exhibit awidthwise variation of density of a reinforcing layer 77 embedded in therubber 38 of the carcass 36, i.e., a variation of a density of thereinforcement layer 77 in the widthwise direction of the track 22. Thedensity of the reinforcement layer 77 refers to a quantity ofreinforcing material of the reinforcement layer 77 (i.e., that materialof the reinforcement layer 77 embedded in the rubber 38) per unit lengthin the widthwise direction of the track 22.

In this embodiment, the reinforcing layer 77 is a layer of reinforcingcables 78 ₁-78 _(R) that are adjacent to one another and extendgenerally in the longitudinal direction of the track 22 to enhancestrength in tension of the track 22 along its longitudinal direction.The density of the layer of reinforcing cables 78 ₁-78 _(R) is greaterin certain regions 79 ₁, 79 ₂ of the track 22 than in other regions 80₁-80 ₃ of the track 22. To that end, in this embodiment, a pitch G ofthe reinforcing cables 78 ₁-78 _(R), which is a distance between centrallongitudinal axes of two adjacent ones of the reinforcing cables 78 ₁-78_(R), varies across the reinforcing layer 77 in the widthwise directionof the track 22. The pitch G of the reinforcing cables 78 ₁-78 _(R) issmaller (i.e., adjacent ones of the reinforcing cables 78 ₁-78 _(R) arecloser to one another) in the regions 79 ₁, 79 ₂ of the track 22 than inthe regions 80 ₁-80 ₃ of the track 22.

More particularly, in this embodiment, each of the regions 79 ₁, 79 ₂ ofthe track 22 overlaps with a respective one of the rolling paths 33 ₁,33 ₂ for the mid-rollers 28 ₁-28 ₆ in the widthwise direction of thetrack 22, while the regions 80 ₁-80 ₃ of the track 22 do not overlapwith the rolling paths 33 ₁, 33 ₂ in the widthwise direction of thetrack 22. There is thus a greater density of reinforcing cables beneaththe rolling paths 33 ₁, 33 ₂ than elsewhere. This may help to bettersupport the mid-rollers 28 ₁-28 ₆ as they roll on the rolling paths 33₁, 33 ₂.

The widthwise variation of density of the reinforcing layer 77 may beimplemented in various other ways in other embodiments.

For example, in other embodiments, as shown in FIG. 38, instead of or inaddition to varying the pitch G of the reinforcing cables 78 ₁-78 _(R)across the reinforcing layer 77 in the widthwise direction of the track22, the density of the layer of reinforcing cables 78 ₁-78 _(R) may begreater in the regions 79 ₁, 79 ₂ of the track 22 than in the regions 80₁-80 ₃ of the track 22 by varying a diameter of the reinforcing cables78 ₁-78 _(R) across the reinforcing layer 77 in the widthwise directionof the track 22 such that the diameter of the reinforcing cables 78 ₁-78_(R) is greater in the regions 79 ₁, 79 ₂ of the track 22 than in theregions 80 ₁-80 ₃ of the track 22 (i.e., cables beneath the rollingpaths 33 ₁, 33 ₂ may have a larger diameter than cables elsewhere in thetrack 22).

As another example, in other embodiments, as shown in FIG. 39, thereinforcing layer 77 may be a layer of reinforcing fabric 89 (e.g., aply of reinforcing woven fibers) and the density of the reinforcingfabric 89 may be greater in the regions 79 ₁, 79 ₂ of the track 22 thanin the regions 80 ₁-80 ₃ of the track 22. To that end, in thisembodiment, a pitch J of elongated fabric elements (e.g., fibers,filaments, strands and/or others) of the reinforcing fabric 89 variesacross the reinforcing layer 77 in the widthwise direction of the track22. The pitch J of the elongated fabric elements of the reinforcingfabric 89 is smaller (i.e., the reinforcing fabric 89 is “tighter” asadjacent ones of the elongated fabric elements are closer to oneanother) in the regions 79 ₁, 79 ₂ of the track 22 than in the regions80 ₁-80 ₃ of the track 22.

2. Self-Aligning Track

In some embodiments, as shown in FIGS. 32 and 33, the track 22 may beself-aligning. The track 22 is configured to oppose lateral movement ofthe track 22 relative to respective ones of the wheels 24, 26, 28 ₁-28 ₆(i.e., movement of the track 22 relative to respective ones of thewheels 24, 26, 28 ₁-28 ₆ in the widthwise direction of the track 22) inorder to align the track 22 within the track system 16 _(i).

In this embodiment, the inner surface 32 of the carcass 36 includes aplurality of aligners 74 ₁, 74 ₂ spaced from one another to alignrespective areas of the inner surface 32 with given ones of the wheels24, 26, 28 ₁-28 ₆. More particularly, in this embodiment, the aligners74 ₁, 74 ₂ are configured to align the rolling paths 33 ₁, 33 ₂ with themid-rollers 28 ₁-28 ₆. In that sense, in this embodiment, the aligners74 ₁, 74 ₂ can be referred to as “rolling path aligners”. The rollingpath aligners 74 ₁, 74 ₂ extend in the rolling paths 33 ₁, 33 ₂ (i.e.,at least part of each of the rolling path aligners 74 ₁, 74 ₂ is locatedin a respective one of the rolling paths 33 ₁, 33 ₂ in the widthwisedirection of the track 22). Each rolling path aligner 74 _(i) isconfigured to exert lateral force components F_(L1), F_(L2) on amid-roller_(x) which tend to align the rolling path 33 _(i) with themid-roller 28 _(x) and thus align the track 22 within the track system16 _(i). The lateral force components F_(L1), F_(L2) act in thewidthwise direction of the track 22 and are oriented opposite oneanother to maintain the rolling path 33 _(i) aligned with the mid-roller28 _(x).

More particularly, in this embodiment, the aligners 74 ₁, 74 ₂ arerecesses. Each recess 74 _(i) has a depth D with respect to a top pointof the inner surface 32 of the carcass 36. For example, in someembodiments, a ratio D/T_(c) of the depth D of the recess 74 _(i) overthe thickness T_(c) of the carcass 36 may be at least 0.05, in somecases at least 0.075, in some cases at least 0.10, in some cases atleast 0.125, and in some cases even more (e.g., 0.15, 0.20 or more). Theratio D/T_(c) may have any other suitable value in other embodiments.

In this example, the recesses 74 ₁, 74 ₂ are longitudinal grooves thatextend in the longitudinal direction of the track 22. In this case, therecesses 74 ₁, 74 ₂ extend along at least a majority of the length ofthe track 22. More specifically, in this case, they extend along anentirety of the length of the track 22.

In some embodiments, the aligners 74 ₁, 74 ₂ of the inner surface 32 ofthe carcass 36 may, in addition to or instead of being aligned with themid-rollers 28 ₁-28 ₆, be aligned with at least part of the drive wheel24 and/or the idler wheel 26. A dimension of each of the aligners 74 ₁,74 ₂ in the widthwise direction of the track 32 may thus be selectedsuch that the aligners 74 ₁, 74 ₂ receive and accommodate at least partof the drive wheel 24 and/or the idler wheel 26.

The aligners 74 ₁, 74 ₂ of the inner surface 32 of the carcass 36 may beimplemented in various other ways in other embodiments.

3. Carcass Comprising a Peripheral Reinforcing Layer

In some embodiments, as shown in FIG. 34, the carcass 36 may comprise aperipheral reinforcing layer 75 adjacent to a periphery of the carcass36 to protect against rupture, such as puncture and/or cracking, orother deterioration of the periphery of the carcass 36 (e.g., due torocks, stubble, or other objects on the ground, etc.).

The peripheral reinforcing layer 75 is adjacent to the periphery of thecarcass 36 in that it is at or near a given one of the ground-engagingouter surface 31 and the inner surface 32 of the carcass 36, i.e.,within a distance P from the given one of the ground-engaging outersurface 31 and the inner surface 32 of the carcass 36 of less than 10%of the thickness T_(c) of the carcass 36 (0≦P/T_(c)<0.1).

In this embodiment, the peripheral reinforcing layer 75 is adjacent tothe ground-engaging outer surface 31 of the carcass 36. Moreparticularly, in this embodiment, the peripheral reinforcing layer 75 isnear the ground-engaging outer surface 31 of the carcass 36 such thatthe distance P is greater than 0 but less than 10% of the thicknessT_(c) of the carcass 36 (0<P/T_(c)<0.10). For example, in someembodiments, the distance P from the peripheral reinforcing layer 75 tothe ground-engaging outer surface 31 of the carcass 36 may be less than5 mm, in some cases no more than 4 mm, in some cases no more than 3 mm,and in some cases even less (e.g., 2 mm or less). The distance P mayhave any other suitable value in other embodiments.

The peripheral reinforcing layer 75 comprises reinforcing material 76having a greater mechanical strength and/or a greater hardness than therubber 38 of the carcass 36.

In this example of implementation, the peripheral reinforcing layer 75is a puncture-resistant layer such that the reinforcing material 76 is apuncture-resistant material having a greater resistance to puncture thanthe rubber 38 of the carcass 36. Also, in this example ofimplementation, the peripheral reinforcing layer 75 is a crack-resistantlayer such that the reinforcing material 76 is a crack-resistantmaterial having a greater resistance to cracking (i.e., crack initiationand/or crack propagation) than the rubber 38 of the carcass 36.

In this embodiment, the reinforcing material 76 is reinforcing fabric.More particularly, in this example of implementation, the reinforcingfabric 76 is woven fabric (e.g., of Kevlar or any other suitablepolymeric material). The reinforcing fabric 76 may be any other suitablefabric in other examples of implementation (e.g., tire cord fabric,metallic fabric).

The peripheral reinforcing layer 75 may be implemented in various otherways in other embodiments. For example, in other embodiments, as shownin FIG. 35, the peripheral reinforcing layer 75 may be at theground-engaging outer surface 31 of the carcass 36 (P=0). In otherwords, in that embodiment, the reinforcing material 76 of the peripheralreinforcing layer 75 constitutes at least part of the ground-engagingouter surface 31 of the carcass 36. As another example, in otherembodiments, the reinforcing material 76 may be any other suitable typeof material (e.g., a sheet of metal or polymer, a layer of transversalpolymeric or metallic cables, a layer of elastomeric material such aspolyurethane different from the rubber 38 inside the carcass 36, etc).

4. Carcass Comprising a Multitude of Reinforcing Fabric Layers

In some embodiments, as shown in FIGS. 36 and 37, the carcass 36 maycomprise a multitude of reinforcing fabric layers 81 ₁-81 _(F) that arestacked in the thickness direction of the track 22. The multitude ofreinforcing fabric layers 81 ₁-81 _(F) includes at least eightreinforcing fabric layers, in some cases at least ten reinforcing fabriclayers, in some cases at least twelve reinforcing fabric layers, in somecases at least fifteen reinforcing fabric layers, and in some cases evenmore (e.g., twenty or more reinforcing fabric layers).

Each reinforcing fabric layer 81 _(x) includes a ply of reinforcingfabric. For example, in some embodiments, the ply of reinforcing fabricof the reinforcing fabric layer 81 _(x) may be a woven fabric (e.g., arubber coated fabric) or a tire cord fabric.

A spacing C of two adjacent ones of the reinforcing fabric layers 81₁-81 _(F) in the thickness direction of the track 22 can be relativelysmall. For example, in some embodiments, a ratio C/T_(c) of the spacingC of two adjacent ones of the reinforcing fabric layers 81 ₁-81 _(F)over the thickness T_(c) of the carcass 36 may be no more than 0.05, insome cases no more than 0.03, in some cases no more than 0.01, and insome cases even less. The ratio C/T_(c) may have any other suitablevalue in other embodiments. For instance, in some embodiments, thespacing C of two adjacent ones of the reinforcing fabric layers 81 ₁-81_(F) may be no more than 4 mm, in some cases no more than 3 mm, in somecases no more than 2 mm, and in some cases even less (e.g., 1 mm orless). The spacing C of two adjacent ones of the reinforcing fabriclayers 81 ₁-81 _(F) may have any other suitable value in otherembodiments.

In this embodiment, respective ones of the reinforcing fabric layers 81₁-81 _(F) have elongated fabric elements (e.g., fibers, filaments,strands, or cords) extending in different directions. That is, elongatedfabric elements of a given reinforcing fabric layer 81 _(i) extend in adirection different from any direction in which elongated fabricelements of another reinforcing fabric layer 81 _(j) extend. Forinstance, in this embodiment, a bias of a given reinforcing fabric layer81 _(i) is different from a bias of another reinforcing fabric layer 81_(j) (e.g., the bias of the reinforcing fabric layer 81 _(i) may differfrom the bias of the reinforcing fabric layer 81 _(i) by +/−45° or anyother suitable oblique angle).

In some embodiments, the reinforcing fabric layers 81 ₁-81 _(F) mayprovide sufficient strength in tension to the track 22 that the track 22is free of any layer of reinforcing cables adjacent to one another andextending in the longitudinal direction of the track 22 (e.g., such asthe reinforcing cables 37 ₁-37 _(M) discussed above).

The reinforcing fabric layers 81 ₁-81 _(F) may be implemented in variousother ways in other embodiments. For example, in some embodiments, thespacing C of adjacent ones of the reinforcing fabric layers 81 ₁-81 _(F)may vary in the thickness direction of the track 22 (e.g., the spacing Cmay be smaller or greater near the ground-engaging outer surface 31and/or the inner surface 32 of the carcass 32 than at the neutral axis72 of the track 22).

In some embodiments, any feature of any embodiment described herein maybe used in combination with any feature of any other embodimentdescribed herein.

Each track system 16 _(i) of the agricultural vehicle 10, including itstrack 22, may be configured in various other ways in other embodiments.

For example, each track system 16 _(i) may comprise different and/oradditional components in other embodiments. For example, in someembodiments, the track system 16 _(i) may comprise a front drive wheel(e.g., the idler wheel 26 may be replaced by a drive wheel) instead ofor in addition to the drive wheel 24. As another example, in someembodiments, the track system 16 _(i) may comprise more or less rollerwheels such as the roller wheels 28 ₁-28 ₆. As yet another example,rather than have a generally linear configuration as in this embodiment,in other embodiments, the track system 16 _(i) may have various otherconfigurations (e.g., a generally triangular configuration with the axisof rotation of the drive wheel 24 located between the axes of rotationsof leading and trailing idler wheels).

While in the embodiment considered above the off-road vehicle 10 is anagricultural vehicle, in other embodiments, the vehicle 10 may beanother industrial vehicle such as a construction vehicle (e.g., aloader, a bulldozer, an excavator, etc.) for performing constructionwork or a forestry vehicle (e.g., a feller-buncher, a tree chipper, aknuckleboom loader, etc.) for performing forestry work, or a militaryvehicle (e.g., a combat engineering vehicle (CEV), etc.) for performingmilitary work, a snowmobile, an all-terrain vehicle (ATV), or any othervehicle operable off paved roads. Although operable off paved roads, thevehicle 10 may also be operable on paved roads in some cases. Also,while in the embodiment considered above the vehicle 10 is driven by ahuman operator in the vehicle 10, in other embodiments, the vehicle 10may be an unmanned ground vehicle (e.g., a teleoperated or autonomousunmanned ground vehicle).

Certain additional elements that may be needed for operation of someembodiments have not been described or illustrated as they are assumedto be within the purview of those of ordinary skill in the art.Moreover, certain embodiments may be free of, may lack and/or mayfunction without any element that is not specifically disclosed herein.

Although various embodiments and examples have been presented, this wasfor the purpose of describing, but not limiting, the invention. Variousmodifications and enhancements will become apparent to those of ordinaryskill in the art and are within the scope of the invention, which isdefined by the appended claims.

1. (canceled)
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 4. A track for traction of anoff-road vehicle, the track being mountable around a track-engagingassembly comprising a drive wheel for driving the track, the track beingelastomeric to be flexible around the track-engaging assembly, the trackcomprising: a carcass comprising an inner surface for facing thetrack-engaging assembly and a ground-engaging outer surface for engagingthe ground; and a plurality of traction projections projecting from theground-engaging outer surface; wherein the carcass has an asymmetricrigidity such that the carcass is stiffer when subject to loadingtending to bend the carcass in a given way than when subject to loadingtending to bend the carcass in an opposite way.
 5. A track for tractionof an off-road vehicle, the track being mountable around atrack-engaging assembly comprising a drive wheel for driving the track,the track being elastomeric to be flexible around the track-engagingassembly, the track comprising: a carcass comprising an inner surfacefor facing the track-engaging assembly and a ground-engaging outersurface for engaging the ground; and a plurality of traction projectionsprojecting from the ground-engaging outer surface; wherein a widthwiserigidity of the carcass when subject to loading tending to bend thecarcass inwardly is different from the widthwise rigidity of the carcasswhen subject to loading tending to bend the carcass outwardly.
 6. Atrack for traction of an off-road vehicle, the track being mountablearound a track-engaging assembly comprising a drive wheel for drivingthe track, the track being elastomeric to be flexible around thetrack-engaging assembly, the track comprising: a carcass comprising aninner surface for facing the track-engaging assembly and aground-engaging outer surface for engaging the ground; and a pluralityof traction projections projecting from the ground-engaging outersurface; wherein a longitudinal rigidity of the carcass when subject toloading tending to bend the carcass inwardly is different from thelongitudinal rigidity of the carcass when subject to loading tending tobend the carcass outwardly.
 7. A track for traction of an off-roadvehicle, the track being mountable around a track-engaging assemblycomprising a plurality of wheels that includes a drive wheel for drivingthe track, the track being elastomeric to be flexible around thetrack-engaging assembly, the track comprising: a carcass comprising aninner surface for facing the track-engaging assembly and aground-engaging outer surface for engaging the ground; and a pluralityof traction projections projecting from the ground-engaging outersurface; wherein the carcass is bent in a widthwise direction of thetrack and deformable in the widthwise direction of the track underloading from respective ones of the wheels.
 8. (canceled)
 9. A track fortraction of an off-road vehicle, the track being mountable around atrack-engaging assembly comprising a drive wheel for driving the track,the track being elastomeric to be flexible around the track-engagingassembly, the track comprising: a carcass comprising elastomericmaterial, an inner surface for facing the track-engaging assembly, and aground-engaging outer surface for engaging the ground; and a pluralityof traction projections projecting from the ground-engaging outersurface; wherein the carcass comprises a first reinforcing layerembedded in the elastomeric material between a neutral axis of thecarcass and the inner surface and a second reinforcing layer embedded inthe elastomeric material between the neutral axis of the carcass and theground-engaging outer surface and having a different stiffness in agiven direction of the track than the first reinforcing layer. 10.(canceled)
 11. (canceled)
 12. (canceled)
 13. (canceled)
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